"They've closed Dover," I said. "And this guy's tweeted that he and his daughter are being held by the cops in Calais." The ferry shuddered a bit and I put down my bad coffee. I refreshed Twitter.
"Do you think they'll stop us when we get off the ferry?"
"I don't know."

I tried to picture what I would say to a French cop. Je vais sur un vin croisière. Désolé, je ne parle pas très bien français.

"I'm gonna tweet the organiser - wait, no, do you reckon the cops'll be watching the hashtag? I'll use this other account. Wait, how tech savvy are cops? I mean if they visited the website and did a whois lookup?"
"If you were a cop, how tech savvy would you be?"
"Okay. So we can't tweet. Okay."

So the French and UK police teamed up to stop the #ConvoyToCalais by stopping protesters at the docks.